- Passive Infrared Sensor (PIR): These are the most common type. Passive infrared sensors are triggered when a combination of heat and movement is detected in the monitored zone. This means a car, truck, person, or any animal will trigger the sensor IF it passes through the monitored zone.
- Magnetometer Bases Sensor: These sensors are designed only to pick up automobiles and work when heavy metallic objects are detected in the monitored zone. The sensor typically has a probe buried just under or parallel to the driveway. When a car or truck drives through the zone, the probe detects and triggers the change in the magnetic field.
- Pneumatic: Do you remember the old gas stations with a rubber hose stretched across the entrance? It would ring a bell as the car rolled over the hose. This type of sensor is called a pneumatic sensor. When a heavy vehicle rolls over the hose, the change in air pressure inside the hose triggers the sensor.
- Break Beam Sensor: These sensors work in pairs, and when someone or something passes between the pair of sensors, they detect that the beam between them was broken and are, thus, triggered.
